Resolves: tdf#63955 clip 19km long line to some sane limit

Change-Id: If9757a5fa2bb93b56b9cf9f566972f687a4a3a45
Reviewed-on: https://gerrit.libreoffice.org/17036Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit d1046e7c)

refactor ensuring polygon has at least a line in it

just split that out into a standalone function, no logic
change

Change-Id: I061d5d716b3fc2a9fb6385e7fb249ce300752130
(cherry picked from commit 83b3349b)
Reviewed-on: https://gerrit.libreoffice.org/17073Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Tested-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

svx/source/sdr/contact/viewcontactofsdrpathobj.cxx

@@ -20,13 +20,14 @@
 
 #include <sdr/contact/viewcontactofsdrpathobj.hxx>
 #include <svx/svdopath.hxx>
+#include <svx/svdpage.hxx>
 #include <svx/sdr/primitive2d/sdrattributecreator.hxx>
 #include <basegfx/polygon/b2dpolypolygontools.hxx>
+#include <basegfx/polygon/b2dpolygonclipper.hxx>
 #include <sdr/primitive2d/sdrpathprimitive2d.hxx>
 #include <basegfx/matrix/b2dhommatrixtools.hxx>
 
 
-
 namespace sdr
 {
     namespace contact
@@ -40,26 +41,14 @@ namespace sdr
         {
         }
 
-        drawinglayer::primitive2d::Primitive2DSequence ViewContactOfSdrPathObj::createViewIndependentPrimitive2DSequence() const
+        static sal_uInt32 ensureGeometry(basegfx::B2DPolyPolygon& rUnitPolyPolygon)
         {
-            const SfxItemSet& rItemSet = GetPathObj().GetMergedItemSet();
-            const drawinglayer::attribute::SdrLineFillShadowTextAttribute aAttribute(
-                drawinglayer::primitive2d::createNewSdrLineFillShadowTextAttribute(
-                    rItemSet,
-                    GetPathObj().getText(0),
-                    false));
-            basegfx::B2DPolyPolygon aUnitPolyPolygon(GetPathObj().GetPathPoly());
-            Point aGridOff = GetPathObj().GetGridOffset();
-            // Hack for calc, transform position of object according
-            // to current zoom so as objects relative position to grid
-            // appears stable
-            aUnitPolyPolygon.transform( basegfx::tools::createTranslateB2DHomMatrix( aGridOff.X(), aGridOff.Y() ) );
-            sal_uInt32 nPolyCount(aUnitPolyPolygon.count());
+            sal_uInt32 nPolyCount(rUnitPolyPolygon.count());
             sal_uInt32 nPointCount(0);
 
             for(sal_uInt32 a(0); a < nPolyCount; a++)
             {
-                nPointCount += aUnitPolyPolygon.getB2DPolygon(a).count();
+                nPointCount += rUnitPolyPolygon.getB2DPolygon(a).count();
             }
 
             if(!nPointCount)
@@ -68,20 +57,66 @@ namespace sdr
                 basegfx::B2DPolygon aFallbackLine;
                 aFallbackLine.append(basegfx::B2DPoint(0.0, 0.0));
                 aFallbackLine.append(basegfx::B2DPoint(1000.0, 1000.0));
-                aUnitPolyPolygon = basegfx::B2DPolyPolygon(aFallbackLine);
+                rUnitPolyPolygon = basegfx::B2DPolyPolygon(aFallbackLine);
 
                 nPolyCount = 1;
             }
 
+            return nPolyCount;
+        }
+
+        drawinglayer::primitive2d::Primitive2DSequence ViewContactOfSdrPathObj::createViewIndependentPrimitive2DSequence() const
+        {
+            const SfxItemSet& rItemSet = GetPathObj().GetMergedItemSet();
+            const drawinglayer::attribute::SdrLineFillShadowTextAttribute aAttribute(
+                drawinglayer::primitive2d::createNewSdrLineFillShadowTextAttribute(
+                    rItemSet,
+                    GetPathObj().getText(0),
+                    false));
+            basegfx::B2DPolyPolygon aUnitPolyPolygon(GetPathObj().GetPathPoly());
+            Point aGridOff = GetPathObj().GetGridOffset();
+            // Hack for calc, transform position of object according
+            // to current zoom so as objects relative position to grid
+            // appears stable
+            aUnitPolyPolygon.transform( basegfx::tools::createTranslateB2DHomMatrix( aGridOff.X(), aGridOff.Y() ) );
+            sal_uInt32 nPolyCount(ensureGeometry(aUnitPolyPolygon));
+
             // prepare object transformation and unit polygon (direct model data)
             basegfx::B2DHomMatrix aObjectMatrix;
-            const bool bIsLine(
+            bool bIsLine(
                 !aUnitPolyPolygon.areControlPointsUsed()
                 && 1 == nPolyCount
                 && 2 == aUnitPolyPolygon.getB2DPolygon(0).count());
 
             if(bIsLine)
             {
+                const SdrPage* pPage = GetPathObj().GetPage();
+                if (pPage)
+                {
+                    //tdf#63955 if we have an extremely long line then clip it
+                    //to a very generous range of -1 page width/height vs +1
+                    //page width/height to avoid oom and massive churn
+                    //generating a huge polygon chain to cover the length in
+                    //applyLineDashing if this line is dashed
+                    double fPageWidth = pPage->GetWdt();
+                    double fPageHeight = pPage->GetHgt();
+                    basegfx::B2DRange aClipRange(-fPageWidth, -fPageHeight,
+                                                 fPageWidth*2, fPageHeight*2);
+                    aUnitPolyPolygon = basegfx::tools::clipPolyPolygonOnRange(aUnitPolyPolygon,
+                                                                       aClipRange, true, true);
+                    nPolyCount = ensureGeometry(aUnitPolyPolygon);
+
+                    // re-check that we have't been clipped out to oblivion
+                    bIsLine =
+                        !aUnitPolyPolygon.areControlPointsUsed()
+                        && 1 == nPolyCount
+                        && 2 == aUnitPolyPolygon.getB2DPolygon(0).count();
+                }
+            }
+
+            if(bIsLine)
+            {
+
                 // special handling for single line mode (2 points)
                 const basegfx::B2DPolygon aSubPolygon(aUnitPolyPolygon.getB2DPolygon(0));
                 const basegfx::B2DPoint aStart(aSubPolygon.getB2DPoint(0));